Kotlin學習筆記(4) infix Functions 内缀函数

Kotlin學習筆記(4)  infix Functions 内缀函数

infix Functions 内缀函数

Member functions and extensions with a single parameter can be turned into infix functions.

程式 

fun main() {

  infix fun Int.times(str: String) = str.repeat(this)        // 1
  println(3 times "Bye ")                                    // 2

  val  pair = "1. Ferrari" to "2. Katrina"                          // 3
  println(pair)

  infix fun String.onto(other: String) = Pair(this, other)   // 4
  val myPair = "McLaren" onto "Lucas"
  println(myPair)

  val sophia = Person("Sophia")
  val claudia = Person("Claudia")

  sophia likes claudia                                       // 5

 
}

class Person(val name: String) {
  val likedPeople = mutableListOf<Person>()
  infix fun likes(other: Person) { likedPeople.add(other) }  // 6
}
輸出畫面
Bye Bye Bye (1. Ferrari, 2. Katrina) (McLaren, Lucas)

1. Defines an infix extension function on Int.
2. Calls the infix function.
3. Creates a Pair by calling the infix function to from the standard library.
4. Here's your own implementation of to creatively called onto.
5. Infix notation also works on members functions (methods).
6. The containing class becomes the first parameter.